Looking over your posting history (see https://ninjastic.space/user/AsongJosh), you’ve made posts on multiple weeks in the past without reaching the maximum (14) that count towards the Activity counter in past 2 week Activity windows. That means that you can catch-up on past Activity on-the-fly now by simply posting, without having to wait for the current Activity 2 week windows to close. This is not easy to grasp, but you should be able to reach Jr. Member as soon as you make another 6 posts (ideally more substantial than to date).

From there on you’ll rank-up at a slower pace, once you meet the requirements of both Merits and Activity shown in the links above.